Is it permissible to break off an engagement from a girl who possesses religious devotion and good character, but whose height one is not convinced by, especially with the fear of the consequences of such a break-off?

If the girl is religious, then do not be averse to marrying her merely because of her short stature; for a woman's shortness is not a defect that should cause her to be rejected. Indeed, the Prophet, peace and blessings be upon him, married Safiyya, may Allah be pleased with her, and she was short. And Allah may bless you in your marriage to her and grant you good offspring. You have done well by performing Istikhara, so if there is good in your marriage to her, Allah will complete it, and if there is evil in it, He will avert her from you. If you break off her engagement, you will not be unjust to her; for engagement is merely a promise, and either party has the right to break it off whenever they wish, though it is disliked to break it off without need.